Top valve for a pressure vessel



July 11, 1961 G. R. ALLEN 2,991,918

TOP VALVE FOR A PRESSURE VESSEL Filed Aug. 20, 1959 HIM!" E3 ll Z in]? I 4 2 1 M 1) 7 I f Iv) Fig.3

INVENTOR.

HIS Y K? United States Patent ce 2,991 918 TOP VALVE FOR A PRESSURE VESSEL George R. Allen, 21 Woodland Drive, Pittsburgh 28, Pa. Filed Aug. 20, 1959, Ser. No. 835,115 2 Claims. (Cl. 222-394) This invention relates to valves, and more particularly to a valve for the upper end of a pressure vessel containing liquefied gas and vapor under pressure.

In withdrawing fluid from a pressure vessel or tank containing both liquefied gas andvapor under pressure, it sometimes is desirable to withdrawn the gas or vapor and at other times to withdraw the liquid. Until now it has been customary to do this by means of an ordinary valve mounted in the top of the tank. To withdraw gas or vapor, the valve is simply opened, but to withdraw the liquid it has been necessary to invert the tank so that the valve will be at the bottom. That often is inconvenient to do, and its also is difiicult to support the tank with the valve beneath it.

It is among the objects of this invention to provide a pressure vessel valve wln'ch isalways used at the top of the vessel and which permits either vapor or liquid to be withdrawn'as desired. 7

In accordance with this invention, the valve has a body that is screwed into the top of a pressure vessel and is provided with an inlet passage extending upward from its lower end, with a restricted upper portion forming a downwardly facing control seat. The upper end of the passage forms an upwardly facing main seat. The body also has an outlet above the passage but connected with it. A main valve closure normally engages the main seat, and means are provided for raising the closure to open the valve. Connected to the bottom of the closure and extending down past the control seat, is a pin that has a smaller diameter than the restricted portion of the inlet passage. A control valve closure is secured to the lower end of the pin and normally is spaced from the control seat to permit vapor in the pressure vessel to flow up past both seats when the main closure is raised to a height less than its maximum distance from the main seat. A tube extends downward from the control valve closure to a point near the bottom of the vessel. The control closure is provided with an opening connecting the space above it with the upper end of the tube. Consequently, upon raising the control valve closure into engagement with the control seat, liquid will be forced up through the tube and out of the valve outlet by the pressure of the expanding vapor in the pressure vessel.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which:

FIG. 1 is a vertical section of my valve mounted on a pressure vessel;

FIG. 2. is a fragmentary vertical section of the valve, showing it opened for escape of vapor;

FIG. 3 is a view similar to FIG. 1, but partly in elevation and showing the valve opened for escape of liquid; and

FIG. 4 is an enlarged horizontal section of the valve, taken on the line IVIV of FIG. 1.

Referring to FIG. 1 of the drawings, a pressure tank or cylinder 1 of well-known construction is provided at its upper end with an internally threaded neck 2, into which the lower portion of a valve is screwed. The casing or body 3 of the valve has a passage 4 extending upwardly from its lower end to form an inlet for the valve. The upper portion of the passage is reduced in diameter, and where its lower end joins the larger diameter portion of the passage a downwardly facing control seat 6 is formed. The valve body above the passage is hollow and has an outlet opening 7, to which a pipe or hose can be connected. The upper end of inlet passage 4 is encircled by an upwardlyfacing main seat 8 that normally is engaged by a stem 10 extending up through the upper end of the valve body. The stem may be raised and lowered in any con-- ventional manner. For example it may be a threaded stem, in which case its projecting upper end is formed for receiving a knob or handle (not shown) for rotating the stem in order to seat or unseat the valve closure.

.Rigidly connected to the lower end of main closure 9, is a vertical pin 12 that extends down through the restricted upper portion of the inlet passage and past control seat 6. The diameter of the pin is materially smaller than that of the surrounding passage so that there can be a free flow of fluid up through the passage when the valve is open. Secured to the lower end of the pin is a control valve closure, which includes an element that generally will take the form of a disc 13. When the main valveis closed as shown in FIG. 1, the disc is spaced a substantial distance from the control seat. A suitable gasket 14 may be mounted on the upper face of the disc for engaging the control seat when the valve is wide open, as in FIG. 3. r

Secured to the central portion of control valve disc; 13 is the upper end of a long tube 16, which forms part oi the valve and extends down to the bottom of the cylinder. The disc is provided with one or more openings 17 through it connecting the upper end of the tube with the upper surface of the disc within the area encircled by gasket 14.

In the operation of this valve, it of course is closed by merely screwing the main valve closure 9 down onto its seat 8 as shown in FIG. 1. When it is desired to withdraw vaporized liquid from the cylinder, the main valve closure is rotated by its stem 10' to raise it from its seat far enough to obtain the desired flow. Vapor flow is established when the main closure and the control closure are both open, as shown in FIG. 2. Since the pressure on top of the liquid around tube 16 is no greater than on the liquid in the tube, because of openings 17, there will be no flow of liquid out of the cylinder at this time. Of course, the control closure disc 13 must not be raised as far as it will go, because that would prevent vapor from flowing up past the disc and the main closure and out through the valve outlet 7.

In case one Wishes to withdraw liquid, instead of vapor, from the cylinder, the main valve closure 9 is raised still higher until the control valve closure gasket 14 firmly engages the control seat 6, as shown in FIG. 3. This will shut ofl flow of vapor from the valve, so the pressure of the vapor in the cylinder above the liquid will force the liquid down and then up through tube 16 and control valve disc openings 17 and on out through the valve outlet.

It will be seen that with this valve the operator may withdraw either vapor or liquid from the cylinder at his option and without changing the position of the cylinder, as has been necessary heretofore. All operations of the valve are controlled from above, by merely turning the valve stem to raise or lower the two connected valve closures. A conventional valve does not need to be altered in any way, except to attach to the lower end of its tapered closure member the pin 12, control valve closure and tube disclosed herein.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. A top valve for a pressure vessel containing liquefied gas and vapor under pressure, the valve comprising a body Patented July 11, 1961.

provided with an inlet passage extending upward from its lower end and having a restricted upper portion forming a downwardly facing control seat, the upper end of the passage forming an upwardly facing main seat, said body having an outlet above said passage and connecting with it, a main valve closure normally engaging said main seat, means for raising the closure to open the valve, a pin of smaller diameter than the restricted portion of the inlet passage connected to the bottom of the closure and extending down past the control seat, a control valve closure secured to the lower end of the pin and normally spaced from said control seat to permit vapor in said vessel to flow up past both seats when said main closure is raised to less than its maximum distance from the main seat, and a tube depending from the control valve closure and adapted to extend down to a point near the bottom of the vessel, said control closure being provided with an opening connecting the space above it with said tube, whereby upon raising the control valve closure into engagement with the control seat expanding vapor in the vessel can force liquid up through the tube and out of said valve outlet.

2. A top valve for a pressure vessel containing liquefied gas and vapor under pressure, the valve comprising a body provided with an inlet passage extending upward from its lower end and having a restricted upper portion forming a downwardly facing control seat, the upper end of the passage forming an upwardly facing main seat, said body having an outlet above said passage and connecting with it, a valve closure normally engaging said main seat, means for raising the closure to open the valve, a pin of smaller diameter than the restricted portion of the inlet passage connected to the bottom of the closure and extending down past the control seat, a disk secured to the lower end of the pin and normally spaced from said control seat, the disk having a diameter larger than said control seat and smaller than said passage belowthat seat to permit vapor in said vessel to flow up past both seats when said valve closure is raised to less than its maximum distance from the main seat, a gasket mounted on said disk for engaging the control seat when said closure is raisedits maximum distance, the disk being provided with a central opening from top to bottom, and a tube having an upper end mounted in said disk opening and adapted to extend down to a point near the bottom of the vessel, whereby upon engagement of said gasket with the control seat expanding vapor in the vessel can force liquid up through the tube and disk and out of said valve outlet.

References Cited in the file of this patent UNITED STATES PATENTS 2,119,643 Mendl June 7, 1938 FOREIGN PATENTS 764,564 Great Britain Dec. 28, 1956 903,463 Germany Feb. 8, 1954 

